Working draft

F11 magic-odd-version

The POSIX magic with a version that is neither 00 nor NULs.

Reject(draft) A strict parser must reject this archive.

Category
framing
Default policy
rejects it
Files
F11-magic-odd-version.tar test archive, 2,048 bytes sha256 6fd234af5e4d11f471ef666bc44e214a2e777e77c571f7066b751a348cdd3a4b
F11-magic-odd-version.jsonexpected result
F11-magic-odd-version.txtannotated blocks
F11-magic-odd-version.pygenerator script

The case

The magic ustar\0 is followed by the version 01, where POSIX requires 00. The default policy accepts only that version, and NULs as some Java archivers write. This case is ambiguous because a reader takes the header in one of three ways: as ustar, ignoring the version; as not in a format that POSIX defines, and stops; or as a v7 header, without the fields that ustar added, which here are empty, so that it gives the same tree.

Decision point: which format the header is in.

Seen in: none of the scanned tarballs.

The archive

Every block of 512 bytes, to scale, with its offset. Hover over a field for its bytes.

F11-magic-odd-version: every block of the archive0x000000header: regular filename [0,100): "a" + 99 NULnamemode [100,108): "0000644" + NUL, 644 (octal)uid [108,116): "0000000" + NUL, 0gid [116,124): "0000000" + NUL, 0size [124,136): "00000000002" + NUL, 2mtime [136,148): "00000000000" + NUL, 0chksum [148,156): "007341\0 ", 3809: the unsigned sum of the header, this field as spacestypeflag [156,157): "0", regular filelinkname [157,257): 100 NULlinknamemagic [257,263): "ustar" + NULversion [263,265): "01"uname [265,297): 32 NULunamegname [297,329): 32 NULgnamedevmajor [329,337): "0000000" + NUL, 0devminor [337,345): "0000000" + NUL, 0prefix [345,500): 155 NULprefixpad [500,512): 12 NULname "a" + 99 NULversion "01"0x000200data2 bytes, then 510 NUL to the end of the block; "a\n""a\n"0x0004002 zero blocks: the end-of-archive markerbytes 0 to 512 of 1024: 512 NUL0x0006002 zero blocks, continuedbytes 512 to 1024 of 1024: 512 NUL0x000800end of fileNULprintable ASCIIspacecontrol character, such as a newlinebyte over 0x7fwritten by the case itself
Every block, as text 
F11-magic-odd-version: must reject

The POSIX magic with a version that is neither `00` nor NULs.

The magic `ustar\0` is followed by the version `01`, where POSIX requires `00`. The default policy
accepts only that version, and NULs as some Java archivers write. This case is ambiguous because a
reader takes the header in one of three ways: as ustar, ignoring the version; as not in a format
that POSIX defines, and stops; or as a v7 header, without the fields that ustar added, which here
are empty, so that it gives the same tree.

Decision point: which format the header is in.
Seen in: none of the scanned tarballs.

0x000000  header: regular file
          name     [  0,100)  "a" + 99 NUL
          mode     [100,108)  "0000644" + NUL  644 (octal)
          uid      [108,116)  "0000000" + NUL  0
          gid      [116,124)  "0000000" + NUL  0
          size     [124,136)  "00000000002" + NUL  2
          mtime    [136,148)  "00000000000" + NUL  0
          chksum   [148,156)  "007341\0 "  3809: the unsigned sum of the header, this field as spaces
          typeflag [156,157)  "0"  regular file
          linkname [157,257)  100 NUL
          magic    [257,263)  "ustar" + NUL
          version  [263,265)  "01"
          uname    [265,297)  32 NUL
          gname    [297,329)  32 NUL
          devmajor [329,337)  "0000000" + NUL  0
          devminor [337,345)  "0000000" + NUL  0
          prefix   [345,500)  155 NUL
          pad      [500,512)  12 NUL
0x000200  data
          2 bytes, then 510 NUL to the end of the block
          "a\n"
0x000400  2 zero blocks: the end-of-archive marker
0x000800  end of file
Every byte, as a hex dump

As xxd writes it: xxd -r makes the archive of it.

00000000: 6100 0000 0000 0000 0000 0000 0000 0000  a...............
00000010: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000020: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000030: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000040: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000050: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000060: 0000 0000 3030 3030 3634 3400 3030 3030  ....0000644.0000
00000070: 3030 3000 3030 3030 3030 3000 3030 3030  000.0000000.0000
00000080: 3030 3030 3030 3200 3030 3030 3030 3030  0000002.00000000
00000090: 3030 3000 3030 3733 3431 0020 3000 0000  000.007341. 0...
000000a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000100: 0075 7374 6172 0030 3100 0000 0000 0000  .ustar.01.......
00000110: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000120: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000130: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000140: 0000 0000 0000 0000 0030 3030 3030 3030  .........0000000
00000150: 0030 3030 3030 3030 0000 0000 0000 0000  .0000000........
00000160: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000170: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000180: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000190: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000200: 610a 0000 0000 0000 0000 0000 0000 0000  a...............
00000210: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000220: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000230: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000240: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000250: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000260: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000270: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000280: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000290: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000300: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000310: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000320: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000330: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000340: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000350: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000360: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000370: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000380: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000390: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000400: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000410: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000420: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000430: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000440: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000450: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000460: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000470: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000480: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000490: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000500: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000510: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000520: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000530: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000540: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000550: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000560: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000570: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000580: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000590: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000600: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000610: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000620: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000630: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000640: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000650: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000660: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000670: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000680: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000690: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000700: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000710: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000720: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000730: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000740: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000750: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000760: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000770: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000780: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000790: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................

What implementations make of it

implementationversionoutcomewhat it makes of it
GNU tartar (GNU tar) 1.35⚠️ acceptstree A: a (2 B, 87428fc5)
bsdtarbsdtar 3.8.10 - libarchive 3.8.10⚠️ acceptstree A: a (2 B, 87428fc5)
BusyBox tarBusyBox v1.38.0, defconfig⚠️ acceptstree A: a (2 B, 87428fc5)
7-Zip7-Zip (z) 26.05 (x64)⚠️ acceptstree A: a (2 B, 87428fc5)
Python tarfile, filter=data, as in pipCPython 3.15.2⚠️ acceptstree A: a (2 B, 87428fc5)
Python tarfile, filter=tarCPython 3.15.2⚠️ acceptstree A: a (2 B, 87428fc5)
Python tarfile, filter=fully_trustedCPython 3.15.2⚠️ acceptstree A: a (2 B, 87428fc5)
node-tartar 7.5.22⚠️ acceptstree A: a (2 B, 87428fc5)
node-tar, stricttar 7.5.22⚠️ acceptstree A: a (2 B, 87428fc5)
tar-fstar-fs 3.1.3, on tar-stream 3.2.2⚠️ acceptstree A: a (2 B, 87428fc5)
Java Commons CompressCommons Compress 1.28.0, Expander, on Java 27.0.1.0.2⚠️ acceptstree A: a (2 B, 87428fc5)
.NET System.Formats.TarSystem.Formats.Tar of .NET 10.0.14, ExtractToDirectory✅ as the verdict sayserror: InvalidDataException: A POSIX format was expected (Ustar or PAX), but could not be reliably determined for entry 'a'.
PHP PharData, as in ComposerPharData of PHP 8.5.12, as Composer's TarDownloader calls it⚠️ acceptstree A: a (2 B, 87428fc5)
Go containerd archive.Applycontainerd v2.4.2, archive.Apply, of go1.27.3⚠️ acceptstree A: a (2 B, 87428fc5)
Rust tartar 0.4.46, unpack⚠️ acceptstree A: a (2 B, 87428fc5)
Rust astral-tokio-tarastral-tokio-tar 0.7.0, unpack⚠️ acceptstree A: a (2 B, 87428fc5)
Rust tar-codec, as in uvtar-codec 0.0.15, with the policies of uv 0.13✅ as the verdict sayserror: at byte 0: invalid tar identity: found [117, 115, 116, 97, 114, 0, 48, 49]
RubyGemsRubyGems 4.0.20 of Ruby 4.0.9, extract_tar_gz⚠️ acceptstree A: a (2 B, 87428fc5)
R untar, internalutils::untar of R 4.6.1, tar = "internal"⚠️ acceptstree A: a (2 B, 87428fc5)
Perl Archive::TarArchive::Tar 3.12 of Perl v5.44.0⚠️ acceptstree A: a (2 B, 87428fc5)
Haskell tartar 0.7.2.0, extract, of GHC 9.14✅ as the verdict sayserror: UnrecognisedTarFormat
Julia Tar.jlTar 1.10.0 of Julia 1.13.3✅ as the verdict sayserror: This does not appear to be a TAR file/stream — invalid version string for tar file: "01". Note: Tar.jl does not handle decompression; if the tarball is compressed you must use an external command lik…
live-bootstrap untarmescc-tools-extra a151c245e512, as live-bootstrap pins it, built with cc⚠️ acceptstree A: a (2 B, 87428fc5)
live-bootstrap untar, --non-strictmescc-tools-extra a151c245e512, as live-bootstrap pins it, built with cc⚠️ acceptstree A: a (2 B, 87428fc5)

Prevalence in release tarballs

Release tarballs of Spack, nixpkgs, Guix and live-bootstrap, and samples of PyPI, crates.io and RubyGems with magic.posix-with-odd-version.

ecosystemtarballswith itshare
Spack37,5530none
nixpkgs18,9900none
Guix10,1680none
PyPI10,0000none
crates.io5,0000none
RubyGems5,0000none
live-bootstrap1710none
total (distinct)82,5860none